Conventionally, a head-mounted display (HMD) is known as a device which can integrate virtual-world video information into real-world video information in real time (for example, see patent document 1). However, although the head-mounted display of the patent document 1 can display the virtual-world video information, the head-mounted display of the patent document 1 cannot change this video information according to movement (in particular, movement of a hand or a leg) of a wearer wearing the head-mounted display or the like. Thus, it is difficult to improve an immersion feeling (presence feeling) of the wearer.